Moscow (AFP) - Moscow on Wednesday said it would be "very difficult" to improve US-Russia relations, which have plummeted to Cold War lows on accusations of election meddling and crises in Syria and Ukraine.

Deputy foreign minister Sergei Ryabkov accused the US of trying to meddle in Russia's internal affairs ahead of a presidential election next month, after Washington indicted 13 Russians for an alleged covert effort to interfere in 2016 US polls.

"Paradoxically, the Americans are taking steps towards meddling in our internal affairs and exacerbating tensions in bilateral relations ahead of the presidential election" in Russia on March 18, Ryabkov told the news agency Interfax.

"Despite this, they continue -- without any foundation or proof -- to reproach us for apparently interfering in their electoral process," he said.

"Of course we in Moscow regret all of this," he said of potential sanctions against the 13 Russians who were indicted last week as part of a US federal government probe.

"It will be very difficult to move relations with the US on from their current state," he said.

Several US congressional committees and special prosecutor Robert Mueller are investigating allegations of Russian interference in the 2016 election and collusion with the campaign of President Donald Trump.

Moscow has long denied any role in election interference.

The Cold War rivals have clashed over crises in Ukraine, Syria and Iran, with reciprocal expulsions of diplomats last year.

Following Russia's 2014 annexation of the Crimean peninsula and the war between Kiev and Kremlin-backed rebels, the US has imposed ever stricter sanctions on Moscow.